Guppies Eating Their Own Fry: Why?

Guppies are a common choice for home aquariums due to their vibrant colours and ease of care. However, one issue that arises for new tank owners is that guppies are known to eat their young, or fry. This behaviour, called filial cannibalism, is common among fish and has puzzled scientists for years. While the exact cause is unknown, it is believed to be related to self-preservation and the survival of the fittest. Guppies show no concern for their fry and will eat them immediately after birth, with both male and female guppies exhibiting this behaviour.

Male guppies do eat their fry

Guppies are one of the most common fish for home aquariums. They are easy to care for, quite hardy, and come in a large range of colours. However, despite their popularity, guppies are known to eat their young, or 'fry'. This behaviour is called filial cannibalism and is common among fish. Guppies are not protective of their offspring and will eat them as soon as they are born.

Male guppies will eat their fry, just like female guppies. This is despite the fact that male guppies do not take part in the childbirth process. Male guppies will eat their young if they are hungry, but this is not the only reason. Male guppies may also eat their fry as a result of stress, or as a means of replenishing energy.

There are a few ways to prevent male guppies from eating their young. One way is to separate the fry when they are born. You can do this by moving the pregnant guppy to a breeding tank or box before it gives birth. Once the guppy has delivered its babies, you can remove it from the breeding tank and put it back into the main tank. You can then introduce the offspring to the main tank when they are big enough that they cannot fit into the adults' mouths.

Another way to prevent male guppies from eating their young is to provide hiding places for the fry. You can do this by adding live or artificial plants to the tank. This will not be as effective as separating the fry, but it can help some of them to survive.

Filial cannibalism is common in guppies

Guppies are generally peaceful, social fish. However, they have been linked to cannibalistic behaviours in their natural aquatic environment, including attacking and killing their young if there is no food. Guppies will abandon their peaceful nature and resort to cannibalism when tank conditions are hostile, such as when the tank is overcrowded and there is a lack of food. In their natural habitat, guppies prefer to feed on small, protein-rich food sources like brine shrimp, micro worms, and water fleas. If these are not available, they may resort to eating their young.

There are several reasons why guppies may engage in filial cannibalism. One theory suggests that guppies eat their fry to cope with depression, frustration, and stress. Another theory suggests that guppies eat their genetically weak offspring to bolster their species' survivability. It is believed that the targeted fry often lack important survival characteristics, such as the ability to hide from predators. By eating their weak offspring, adult guppies are increasing the survivability of the species as a whole.

Additionally, guppies may eat their fry as a form of population control. Guppies reproduce prolifically, and overpopulation is quite common. By eating their young, guppies can curb the problem of overpopulation. Filial cannibalism may also be a result of a spill-over response prompted by stress factors, which enhances the self-preservation instinct of the fish. However, this is not a satisfactory explanation as guppies in low-stress environments have also been observed eating their fry.

To prevent guppies from eating their fry, it is recommended to separate the female guppy before she gives birth, either by using a breeding box in the tank or moving her to a separate tank. Another method is to provide hiding places for the fry by growing live plants or using tank decorations. These methods can help increase the chances of survival for the fry, but they are not as effective as separating the adults and fry completely.

Guppies eat their fry due to stress

Guppies are known to eat their young, a phenomenon called filial cannibalism. While the exact cause of this behaviour is unknown, it is speculated that it could be triggered by self-preservation instincts, or nature's way of ensuring the survival of the fittest. Interestingly, female guppies may spare their young shortly after giving birth, but this changes as the female recovers from the stress of labour.

Stressful conditions in an aquarium can drive any creature to attack smaller, weaker fish, and this includes their own offspring. Even if the tank has plenty of food, guppies may respond to a perceived scarcity of resources by eating the fry to store energy. In some cases, the goal may be to eliminate genetically weak offspring.

Stress in guppies is caused by unsuitable conditions, such as low water temperature, small or overcrowded tanks, aggressive tank mates, or poor water conditions. Guppies are tropical fish and require warmer waters with a stable temperature between 75-78 °F (24-26 °C). A small or overcrowded tank can also cause stress, with the recommended volume of water per adult guppy being 1 US gallon (4 litres). Aggressive tank mates can also induce stress, as guppies are peaceful fish and will try to hide or run away from more aggressive species. Poor water conditions, such as high levels of ammonia, nitrites, and nitrates, can also induce stress in guppies.

Therefore, it is important to provide optimal conditions for guppies to reduce their stress levels and discourage them from eating their fry. This includes maintaining the recommended water temperature and volume, choosing peaceful tank mates, and regularly changing the water to prevent a buildup of waste products and ensure optimal water conditions.

Guppies eat their fry due to lack of food

Guppies are known to eat their young, a phenomenon called filial cannibalism, which is common in the animal kingdom and especially prevalent among fish. While the exact cause of this behaviour is unknown, there are several theories as to why it occurs. One theory suggests that guppies may eat their fry due to a lack of food, as they may be responding to a perceived scarcity of resources by eating their offspring to store energy.

Guppy fry have a smaller chance of survival when there are many adult fish in the tank, as the adults will eat their young. Therefore, if you are breeding guppies and want to prevent them from eating their fry, it is recommended to separate the pregnant female before she gives birth, either by using a breeding box within the tank or moving her to a separate tank. The breeding box method is a temporary solution, as fry should not be kept in the box for longer than two weeks, as it may stunt their growth.

Another way to prevent guppy fry from being eaten is to provide hiding places in the tank, such as live plants or tank decorations. This method is not as effective as separating the adults and fry, but it can still improve the fry's chances of survival.

It's important to note that guppies are not the only fish that exhibit filial cannibalism. Mollies and platies, for example, also engage in this behaviour. While it may be disturbing to fish owners, filial cannibalism is a natural occurrence and does not harm the adult fish or the water chemistry.

How to prevent guppies from eating their fry

Guppies are known to eat their young, a phenomenon called filial cannibalism. This is common in fish and can be triggered by self-preservation instincts or nature's way of ensuring the survival of the fittest.

Separate the Pregnant Female Guppy

The most effective way to prevent guppies from eating their young is to separate the female before she gives birth. Move the pregnant female to a separate tank or use a breeding box in the same tank to isolate her from the other adults. Guppies have a mating ritual where the male dances and chases the female. After this ritual, the female will likely become pregnant and give birth in about a month. During pregnancy, the female guppy will develop signs such as a dark patch on the backside of the stomach, appearing fat or bloated, and exhibiting reclusive behaviour. Once you notice these signs, you can move the female guppy to a separate tank or breeding box.

It is important to avoid isolating the female too early as it can cause stress and lead to spontaneous abortion. If she doesn't give birth within 24 hours of being separated, return her to the original tank and continue observing for signs of an impending birth. When moving the female, ensure that the water temperature, pH, and other parameters match those of the original tank to prevent stress.

Use a Breeding Box or Net

A breeding box or net is a hatchery that can be placed within the community tank. It allows for physical separation of the pregnant female guppy from other adults while still exposing the fry to the same water conditions. The breeding box or net makes it easier to monitor the birth and keep the newborn fry safe. However, the mother may devour the babies, so it is recommended to remove her from the breeding box and return her to the community tank after giving birth.

Breeding boxes are a good temporary solution, but fry should not be kept in them for longer than two weeks to prevent stunted growth.

Provide Hiding Places with Live Plants and Decorations

Another way to prevent guppies from eating their fry is to provide hiding places in the tank. You can do this by adding live plants and decorations, which offer cover for the fry to elude adult fish. Live plants also have additional benefits, such as providing food for the fry and helping to control toxin levels in the aquarium.

While this method may not be as effective as separating the adults and fry, it can improve the chances of survival for some fry.

Frequently asked questions